This chapter explores the period of fourth age that is characterised by the transition to impairment and advanced age. With much of the gerontological literature addressing the earlier part of late life, the attempt here is to understand the transition into later periods of the lifecourse. The chapter begins by outlining ongoing attempts to establish what is meant by the fourth age, and points to mounting tensions from social and psychological perspectives. Rather than focusing on the dominant interpretations based on age or stage, it draws on the significance of this change and the associated socio-cultural meanings and processes involved. It considers how, while structured by biophysical notions of advanced age and impairment, this period is marked by a decline-based discourse that is significant as far as interpretations of continuity and change are concerned. What is important from a social perspective is that for older people, the period conceptualised as the ‘fourth age’ is a highly significant social construction involving personal experiences of making meaning of impairment in late life.

This chapter draws on older people's experiences in order to confront the knowledge on transitions and late life. The accounts given challenge how impairment in late life is unrecognised as a transition, as well how dominant understandings depict late life as a period of illness and decline. The stories from older people draw attention to the socio-cultural constructs and the personal interpretations of such change. Specifically, these stories highlight the importance of the assigned identity; the tension between achieving continuity amid change; liminality and the uncertainty of ‘being between’; and the structured and interpretive nature of vulnerability across the lifecourse. Through these issues, older people with impairments in late life become located within and between dominant and alternative models of late life transitions. The accounts highlight the importance of considering the socio-cultural context within which experiences are interpreted, the emotional significance of impairment, and the cumulative nature of disadvantage. Questions explored in this chapter include:

• • What approaches have been used to understand age and impairment in late life? What trends can be found within the social, biological and psychological literature?

• • How can the relationships between age and impairment in late life be explained? What characterises this experience?

• • Can the fourth age, or the acquisition of impairment in late life, be considered to represent a major transition in late life?